Manufacture of calorific gas



Oct. 20, 1953 J. l. `YELLOTT 2,656,264

MANUFACTURE OF CALORIFIC GAS Filed Aug. 28, 1947 JOHN YELLoTr. n

Patented Oct. 20, 1953 MANUFACTURE F CALORIFIC GAS John I. Yellott,Cockeysville, Md., assigner to Institute of Gas Technology, Chicago,Ill.

Application August 28, 1947, Serial No. 771,132

3 claims. l

This invention relates to a method and apparatus for the continuousgasification of comminuted carbonaceous material involving, as laninitial step, the flash pulverization of coal or the like followed byadmixture of air or oxygen to the resulting rapidly flowing gaseoussuspension of comminuted coal particles which is raised to a temperatureadapted to bring about a gas forming reaction between the comminutedcoal particles and the gaseous suspension medium.

Reference is made to my copending application Serial No. 530,177, filedApril 8, 1944, and now forfeited, and entitled Method of and Apparatusfor Flash Pulverizing (of which the present application is acontinuation-impart), and to my copending application entitledComminution Device, led on or aboutrJuly 22, 1947, Serial No. 762,589. Acontinuation-in-part of the f'lrst application has now issued as PatentNo. 2,515,- 542. The second application has now issued as Patent No.2,515,541. flhese applications disclose a method for flash pulverizinginvolving the steps of forming a rapidly moving entrainment of coarsesolid particles to be comminuted in a gas under pressure moving througha constricted open-ended tube. As said entrainment rapidly moves throughsaid constriction toward said opening, the gas is instantaneouslyaccelerated, at said constriction, to critical velocity and there iseffected a practically instantaneous pressure drop that explosivelyshatters the entrained coarse particles to form a gaseous entrainment ofshattered particles. In such flash pulverizing apparatus, the tubecontaining the entrainment of the coarse particles to be shattered maybe constricted at the open end of the tube or further upstream. Ineither case, there is a conversion of pressure head into kinetic energy,so that the `final gaseous entrainment of comminuted particles movesmore rapidly but under less than onehalf of the initial pressure(upstream of the constriction) of the original gaseous entrainment ofrelatively coarse particles to be comminuted.

According to the present invention, the suspension of coal particlesshattered by flash pulverization, as by the use of superheated steam,has air or oxygen admixed therewith and the re* sulting mixture isconducted into a gasifying chamber in which the mixture travels along avortical path. A gasifying temperature is maintained in this chamber bypartial combustion of the shattered particles, by heating the chambersurfaces to effect heat transfer therefrom by radiation or by contact,or by a combination of these two methods. The ratio of air or oxygen tosteam may be controlled to prevent fusion of the ash. Gaseous productswith ash and unreacted fuel will leave the gasifying chamber to enterdust and heat recovery means.

It is therefore an important object of the present application toprovide method and apparatus for producing gas from carbonaceousmaterial such as coal in which steam or air or oxygen are utilized bothto pulverize or comminute the coal and to enter into a gasifyingreaction between comminuted coal and added air or oxygen.

Another important object of the present invention is to provide methodand apparatus for the production of gas in which coal or the like isinitially flash pulverized, as in superheated steam under pressure, airor oxygen is admixed with the resulting gaseous suspension of comminutedcoal, the resulting mixture is caused to move along a vortical pathwhile partial combustion and gas formation is eiected at an elevatedtemperature, and ash and heat are thereafter removed or recovered fromthe gas thus formed.

Other and further objects and features of the present invention willbecome apparent to those skilled in the art from the followingdescription of the apparatus shown in the appended drawings and from theaccompanying claims.

On the drawings:

Figure 1 is a diagrammatic representation, in vertical cross-sectionalview, with 'parts shown in elevation, of an illustrative example of an'apparatus according to the present invention; and

Figure 2 is a fragmentary cross-sectional view taken along the lineII-II in Figure 1.

In the drawings, the reference numeral I0 indicates generally anenclosed furnace made of heat resistant and heat insulating material andincluding an upright portion loa of generally cylindrical rform havingits top closed by a roof por? tion mb pierced by a central aperture |0c..On the left-hand side, `and near its top, the furnace 4portion lila ispierced by an aperture Ind extending-transversely and in parallelismwith the plane of section in Figure 1. Further, at the opposite side,and near its bottom, the cylindrical portion ia is pierced by anaperture loe. The furnace generally indicated at lil also includes a.relatively smaller, horizontally extending generally cylindricalportion luf branching off from `the v lowermost portion of -the uprightcylinder 10a and having its end closed by a vertical wall Ing centrallypierced by an aperture lh.

In the furnace portion lf hot gases or combustion gases are generated bymeans -of a device described hereinbelow, for generating superheatedsteam in a coil I2 within and concentric with the furnace portion IDf.'Steam is introduced into the coil I2 through a conduit I3, and theresultant superheated steam is withdrawn through a conduit I4. From thefurnace portion IUf, the hot gases or the combustion gases, as the casemay be, are discharged into the cylindrical furnace portion Ia andtravel upwardly for discharge: through a conduit I5 having a terminalportion tted into the aperture |0c. While passing upwardly through thefurnace portion Illa, the hot gases or the combustion gases transferheat to a metallic upright structure Inade'upof two spaced cylindricalwalls I'I and I8 concentric with the upright furnace portion Illa andspaced from each other and from the uprightA furnace portion IIla so asto dei-lne a central upright passage 20, an annular interspace 2|between the walls II and I8, and an outermost annular space 22 betweenthe wall I8 and the insides ofv the upright furnace portion Ia. Thecylindrical walls Il' and I8 are spaced from the roof |019 of theupright furnace portion Illa as well as from the bottom thereof, beingsupported within the furnace by any suitable means such as legs (notshown). Further, the annular space 2|. is. closed off at' the top andbottom thereof, respectively, by generally horizontal annular walls 23and 24. It will be noted that, in this manner, there is' provided avertical annular chamber 2| not accessible to the hot gases entering theupright furnace portion I0a. These gases nevertheless havefree passageupwardly through the furnace portion Ia on both sides of the annularspace. 2|, through .space 22 and through the centrai passage V2|). Thus,as will be described in more detail hereinbelow, when the space 2| isutilized as a gasifying chamber, heat from the hot gases or combustiongases generated in the furnace portion I0f can contribute tothemaintenance of the chamber 2| at any desired temperature.

The materials entering into the gasifyingreaction within the annularspace 2| are supplied thereto by the following devices. materal to begasied, such as coarsely fragmented coal, is received by a hopper 25having a conical bottom. The hopper 25 is provided at its discharge endwith a double bell and hopper de- I vice or other gas lock means 26 fordischarge into a tank 21 having a conical bottom discharging into aconduit 28. The latter communicates directly with and serves to conductthe coal to be comminuted into horizontally extending tubularly enclosedscrew feeder or conveyor 29 driven by a motor 30. The screw conveyor 29moves the coal or other carbonaceous material to be comminuted into ahorizontally extending conduit 30 by way of a vertical extension 3| ofthe enclosed conveyor 29. Gas under pressure, such as superheated steam,is introduced into the upper 'part of the tank 2'1 through a valvedconduit 3| tapping the conduit I4 and also serving to supply the conduit3|)A with compressed gas.

The right-hand end portion of the conduit 30, downstream of the conduit3|, is sharply constricted, as at 35, to form a convergent-divergentnozzle followed by a conduit 36 of at least the same diameter as theconduit 3D but smaller than the aperture Ind. This conduit 36 extendsthrough the aperture Id into the upper part of the furnace portion II'Iaand discharges tangentially into the annular space 2I, as through theaperture I8a.

The tube 36 is contained within a generally cy- Carbonaceous lindricaltubular member |40 fitting into and projecting from both sides of theaperture Illd. Within the upright furnace portion Ia, the tubular member|40 extends horizontally and communicates tangentially with the space2|, as by an aperture Ib. Outside the upright furnace portion IOa, thetubular member |40 extends about the conduit 36 to a point short of thenozzle and is closed off from the outside atmosphere by an annular endwall |4I tting around the conduit 36. A pipe |42 serves to admit oxygen,air or the like into the space between the conduit 36 and the tubularmember 36, for more or less tangential discharge into the space 2 I,along with the suspension of comminuted coal or the like and steam orother compressed gas issuing from the conduit 36.

As disclosed hereinabove, gas formation occurs within the space 2| bythe interaction between the comminuted coal, steam, air or oxygen or thelike tangentiallyl discharged into the annular space 2| through theconduit 36- and the tubular member |40. Gasication of the coal takesplace at an elevated temperature brought about by partial combustion ofthe comminuted coal and/or by heat transmitted through the walls I'I andI8 from combustion gases generated in the horizon tal furnace portionIllf. While this combustion may be brought about by conventional meansand methods, for instance, by the injection of liquid or pulverizedfluid into the furnace portion IIlf through the aperture Inh, I preferto generate hot gases in the furnace portion |0f by means and methodsdescribed as follows.

-Solid fuel to be comminuted, such as coarsely fragmented coal, isreceived in a hopper 40 having a conical bottom and provided at itsdischarge end with a double bell and hopper device or other gas lockmeans 4I for discharge into a tank 42 having a conical bottomdischarging into a conduit 43. The latter communicates directly with andserves to conduct the coal or other fuel to be comminuted into ahorizontally extending tubularly enclosed screw feeder or conveyor 44driven by motor 45. The screw conveyor 44 moves the coal or other fuelto be comminuted into a horizontally extending conduit 46 by way of avertical extension 41 of the tubularly enclosed conveyor 44. A gas underpressure, such as superheated steam, is admitted into the upper part ofa tank 42 through a valved conduit 48 tapping the conduit 40 and alsoserving to supply the conduit 46 with compressed gas. If desired,superheated steam, air or other compressed gas may be fed to the conduit48 from a valved line 49.

The right-hand end portion of the conduit 41 downstream of a dischargeopening of the conduit 41 is sharply constricted, as at 48, to form aconvergent-divergent nozzle followed by a short conduit 49 at least aswide as the conduit 46 but not as wide as the furnace aperture |611.,through which the conduit 49 extends into the furnace portion If. Atubular member 56 nts into the aperture Ih. and extends about theconduit 49 outside the furnace wall Ib, short of the nozzle 48. Thetubular member 58 is closed 01T from the atmosphere by an annular endwall 5I fitting the conduit 49. Oxygen or air may be admitted into theconduit 56 and into the furnace If to a pipe 52. Thus, coal comminutedon passage through the conduit 46 and nozzle 43 and suspended insuperheated steam, together with air from the conduit 5|), enters thefurnace portion If, for partial or complete combustion, withaccompanying generation of heat and upward flow through thevfurnaceportion Ia. (through the spaces'2 and 22), with concurrent transmissionof heat through the tubular walls I1 and I8, being discharged from thefurnace I0 through the conduit I5. The latterv takes the hot gasesthrough a waste-heat boiler 55 receiving water from a conduit 56 anddischarging steam into the conduit I3, the cooled combustion gases beingdischarged through a conduit 51 for venting into the Vatmosphere (in thecase of gases resulting from complete combustion) or for recovery andutilization (inthe case of caloriiic gases resulting from incompletecombustion).

wThe gases generated in the space 2I pass through a horizontal conduitt4 communicating with the space 2I near the bottom thereof andprojecting outwardly from the furnace Illa through the furnace apertureI 0e, to discharge said gases tangentially into a cyclone separator 6Iprovided with double spaced side walls for receiving cooling water. Fromthe cyclone, the ash is discharged downwardly through a conduit 53,while the gases are discharged upwardly through a conduit 54 into awater scrubber 65 receiving scrubbing water through a conduit 55 anddischarging heated scrubbing water through another conduit 61. Finally,the scrubbed gases are led through a conduit 68 to a storage orutilization device.

'Ihe heat content of the scrubbing water dis- -v charged through theconduit 61 is recovered in a heat exchange device 10 and, after heatexchange, discharged therefrom through a conduit 1I. In the heatexchange device 1U, heat is transferred to water entering through aconduit 12 and, after heating, conducted through a pipe 13 to the waterjacket of the cyclone 6I. After further heating in said. jacket, thewater is suitably discharged into the conduit 56 for conversion intosteam 4in the boiler 55.

At the start of the operation of the above de scribed apparatus, coal orother carbonaceous fuel in coarsely fragmented form is charged throughthe hopper 45 and the gas lock 4I into the tank 42. Superheated steam orother gas under pressure is initially introduced through the conduit 49and caused to flow through the conduit 48 into the tank 42 and, rapidly,through the conduit 45. The screw conveyor 44 is operduit l46 willattain approximately the same speed 'as the gas flowing through theconduit 45 before reaching the nozzle 48. Instantaneous expansion occurscontinuously as the compressed gas in the pipe 46 passes through anozzle 48 and causes an explosive shattering of the solid particles byvirtue of the expansion of the compressed air, steam or other gascontained within the porosities of the solid particles. From the nozzle45, the expanded gas-comminuted coal mixture passes into the conduit 49and is discharged into the interior of the furnace portion IIJf.

The operating pressure for the steam or other gas in the conduit 45should be at least 5 lbs. per sq. in. and may be as high as '15G lbs.per sq. in. If upstream pressures of 5 lbs. per sq. in. are used,however, the required downstream pressure will be below atmospheric andthe degree of comminution is not so great. Superheated steam at atemperature of between 350 and 450" or -higher is suitably employed. At.the preferred` operating pressure of about 200 lbs. per sq. in. orhigher in the conduit 46, the pressure in the conduit 49 may suitably beabout 60 lbs. per sq. in. or less.

It should be understood that Vthe extent of comminution is determined,inter alia, by the pressure level of operation, by the differencebetween the upstream and the downstream pressures on the two sides ofthe nozzle 48, by the ratio of gas to solids passing through the nozzle48, and by the rate of movement of solids through the nozzle 43. Finercomminution is effected by the maintenance of maximum upstream andminimum downstream pressures, bythe use of relatively large amounts ofgas as compared to the amount of solids, and by the establishment ofrapid flow of solids through the nozzle. By far the best results areobtained when the pressure upstream of a nozzle is at least twice thepressure downstream of a nozzle and when, consequently, criticalvelocity is reached in the nozzle. Air or oxygen may be admitted intothe furnace portion luf through the pipe 52 and the tubular member 5I ata ratio (with respect to the amount of comminuted coal introduced intothe furnace portion Ilf) such as to bring about complete combustion ofthe coal. However, the amount of air admitted may be so restricted as tobring about only a partial combustion of the coal. Once combustion(partial or complete) has been established within the furnace portionIUf, and the water passing through the boiler 55 has been converted intosteam and this steam'v has been superheated to a desired extent onpassing through the coil I2, the ilash pulverizing device including thenozzle 48 may be operated from this superheated steam, the supply ofsteam, air or other gas through the pipe 49 being shut oil.

When, as described hereinabove, combustion in the furnace portion Iilfhas been well established, andhot gases ow through the furnace portionIa, then flash pulverization may be initiated at the nozzle 35, byintroduction of coal and superheated steam into the tank 21, operationof the screw conveyor 29, and establishment of rapid flow of steamthrough the conduit 38, with resultant passing of a suspension of coarsecoal particles in gas through the nozzle 35. Flash pulverization anddischarge of a suspension of comminuted coal particles in steam throughthe conduit 36 is effected exactly as described hereinabove inconnection with ash pulverization of coal in the comminuting deviceincluding the nozzle 48 and the discharge conduit 49. `The suspension ofcomminuted coal particles in steam discharged from theo onduit 35through the aperture Isa tangentially into the space 2l flows in avortical path downwardly through the space 2i, is discharged from thisspace through conduit 60, and enters the` cyclone 5I, Where ashisseparated and discharged downwardly through the conduit 63, while theseparated gas flows through the conduit 64 into the scrubber 65 andthence through the conduit 58 to a storage or utilization device.

The .gas forming reaction within the space 2| includes a reactionbetween the coal and the oxygen (or air) admitted from the pipe 42through the tubular member 45 .by the way of the orifice |81) into theannular space 2| for admixture with the comminuted coal-streamsuspension discharged into the annular space 2I `through the conduit 35by way of the aperture I8a. Thus, the oxygen (or air) also oWs down'-wardly in the space 2I along a vortical path, in

7 ini'ainiauf,` admix'ture with the steam and commlnuted coa-1particles.

Y The temperature to be maintained in the gas owing vortically throughthe space 2| is preferably such as not to bring about complete fusionor, at most, with such slight softening of the ash asV might stillproduce an ash capable of being carried in suspension by the gases. Thetemperaturein question will vary according to the fusion point of theash derived from the particular coal being utilized and will generallyrange from about a maximum of 1800 to a maximum of 2800o F.

The actual temperature in the annular space 2| is reached as a compositeresult of a number of factors; Heat generation in the apparatus of thepresent invention is effected (l) by partial or complete combustion inthe furnace portion f and (2) by partial combustion in the space 2Theamount of heat generated in the furnace portion |0 depends on theamount of coal introduced, the amount of air or oxygen introduced yfromthe pipe 52i the amount of steam introduced along with the coal (steamhaving a tendency to lower combustion temperature in the furnace portionIOJ due to an endothermic water gas reaction between steam and coal) ,Yand the amount of heat abstracted by Water in the coil l2; Lilie- Wise,the amount of heat generated in the space 2| depends upon the amount ofcoal introduced into the space 2 l, the amount of air or oxygenintroduced into the space 2|, and the amount of steam introduced intothe space 2|. Further, in bothA the heat generating reactions, theparticular reactions effected iniluence the amount of heat generated, asby a more or less complete combustion. Further, the temperature in thespace 2| depends upon the rate of flow, both of gases generated in thefurnace portion If and of gases through the conduits 36 and 40discharging into the 'space 2|, as well as on the rate of flow of gasthrough the conduit I5, the boiler 55, the cyclone 6|, and the conduits6|), B4 and 68. These various factors areso balanced by the operator asto bring about the desired temperature in the space 2 l v Hot gases ofvarious compositions may be produced within the furnace portion lilanddischarged through the conduit 57 'and produced in the space 2| anddischarged through the conduit 68. In each instance, the exactcomposition of the gas Will vary according to the amount of coal,-oxygen or air, steam and the temperature. These conditions can beadjusted by the operator` according to well known principles to producewhatever gas feed or whatever specific composition may :be desired. yWith the minimum amount of steam required for flash pulver'ization andair, -say, about '700 cubic 'feet for each 20 pounds of coal, a producergas may be generated; by operating with about 230 cubic feet of air, 170cubic feet of oxygen and 13 pounds of steam for each 32 -pounds of coal,a mixed gas may be produced; by

dper'ating with 2'70 pounds of oxygen and 20 'pounds of steam for each40 pounds of coal, .blue gas may be generated, 'at a temperature of from1700 to 1900o F.

Many details of construction and operation :may be varied within a wirerange without departing from the principles of this invention, and it istherefore not my purpose to limit the patent grantedv on this inventionotherwise than necessltated by the scope of the appended claims.

I claim as my invention:

l. The method of manufacturing a calorific gas --from granular coalwhich comprises providing a l source of gas under 'a pressure of atleast v'e pounds per square inch; continuously and uninterruptedlydischarging compressed gas from said source While conning the dischargedgas to establish a stream of compressed gas flowing uninterruptedly andcontinuously from said source to and past a discharge point spaced fromsaid source; concurrently, continuously and uninterruptedly introducingsaid granular coal into said stream ahead of said discharge point foracceleration and suspension of said granules by said gas ahead of saiddischarge point; at said discharge point establishing and continuouslyand uninterruptedly maintaining a sharp gas pressure gradient, thepressure of said granule-suspending gas being instantaneously reduced assaid granulesus'pending gas continuously and uninterruptedly flows pastsaid discharge point; said stream of compressed gas having asubstantially uniform cross sectional area upstream of said dischargepoint and being sharply Constricted only at said discharge point wherebythe total pressure drop in said stream is concentrated at said dischargepoint; the drop in gas pressure at said discharge point beingcontinuously and uninterruptedly maintained at a value of at least fivepounds per square inch and the gas pressure immediately downstream ofsaid discharge point being reduced at least to a point where furtherdownstream pressure reduction will not bring about a substantiallyincreased weight rate of flow past said discharge point; said coal beingintroduced into said stream in the form of granules smaller than thecross section of said stream at said discharge point; each of saidsuspended granules being carried in suspension by said streamingcompressed gas along a substantially straight path to and past saiddischarge point and there further accelerated and subjected to saidinstantaneous drop in gas pressure whereby said granules aredisintegrated and there is formed a flowing suspension of shattered coalparticles in expanded gas; immediately forming said suspension into avortex; incorporating with said vortex, in a stream separate from saidowing suspension of shattered coal particles in expanded gas, a gascapable of reacting at an elevated temperature with said coal particlesto form a caloric gas; and maintaining said vortex at an elevatedtemperature to bring about generation of a caloric gas.

2. The method of manufacturing a caloric gas from granular coal whichcomprises providing a source of steam under a pressure of at least fivepounds per square inch; continuously and uninterruptedly dischargingcompressed steam from said source while confining the discharged steamto establish a stream of compressed steam flowing uninterruptedly andcontinuously from said source to and past a discharge point spaced fromsaid source; concurrently, continuously and uninterruptedly introducingsaid granular coal into said stream ahead 'of said discharge point foracceleration and suspension of said granules by said steam ahead of saiddischarge point; at said discharge point establishing and continuouslyand uninterruptedly maintaining a sharp steam pressure gradient, thepressure of said granule-suspending steam being instantaneously reducedas said granule-suspending steam continuously land uninterruptedly iioWspast said discharge point; said stream of compressed steam having asubstantially uniform cross sectional area upstream of said dischargepoint and being sharply constricted only at 'said discharge pointwhereby the total pressure drop in said stream is concentrated at saiddischarge point; the drop in steam pressure at said discharge pointbeing continuouslr an-d uninterruptedly maintained at a value of atleast iive pounds per square inch and the steam pressure immediatelydownstream of said discharge point being reducedl at least to a pointwhere further downstream pressure reduction will not bring about asubstantially increased weight rate of flow past said discharge point;said coal being introduced into said stream in the form of granulessmaller than the cross section of said stream at said discharge point;each of said suspended granules being carried in suspension by saidstreaming compressed steam along a substantially straight path to andpast said discharge point and there further accelerated and subjected tosaid instantaneous drop in steam pressure whereby said granules aredisintegrated and there is formed a flowing suspension of shattered coalparticles in expanded steam; immediately and in a tangential directioninjecting said last mentioned suspension into a cylindrical space toform said suspension into a vortex; injecting into said vortex, in astream separate from said flowing suspension of shattered coal particlesin expanded steam, an oxygen-containing gas capable of reacting at anelevated temperature with said coal particles to form a caloric gas; andmaintaining said vortex at said elevated temperature to bring about areaction between said coal particles and sai-d gas generating a caloricgas.

3. The method of manufacturing a caloric gas from granular coal whichcomprises providing a source of steam under a pressure of at least vepounds per square inch; continuously and uninterruptedly dischargingcompressed steam from said source while confining the discharged steamto establish a stream of compressed steam owing uninterruptedly andcontinuously from said source to and past a discharge point spaced fromsaid source; concurrently, continuously and uninterruptedly introducingsaid granular coal into said stream ahead of said discharge point foracceleration and suspension of said granules by said steam ahead of saiddischarge point; at said discharge point establishing and continuouslyand uninterruptedly maintaining a sharp steam pres# sure gradient, thepressure of said granule-suspending steam being instantaneously reducedas said granule-suspending steam continuously and uninterruptedly flowspast said discharge point;

said stream of compressed steam having a substantially uniform crosssectional area upstream I10 o1' said discharge point and being sharplyconstricted only at said discharge point whereby the total pressure dropin said stream is concentrated at said discharge point; the drop insteam pressure at said discharge point being continuously andunnterruptedly maintained at la value of at least ve pounds per squareinch and the steam pressure immediately downstream of sai-d dischargepoint being reduced at least to a point where further downstreampressure reduction will not bring about a substantially increased weightrate of flow past said discharge point; said coal being introduced intosaid stream in the form of granules smaller than the cross section ofsaid stream at said discharge point; each of said suspended granulesbeing carried in suspension by said streaming compressed steam along asubstantially straight path to and past said discharge point and therefurther accelerated and subjected to said instantaneous drop in steampressure whereby said granules are disintegrated and there is formed aflowing suspension of shattered coal particles in expanded steam;immediately and in a tangential direction injecting said last mentionedsuspension into a cylindrical space to form said suspension into avortex; injecting into said Vortex, in a stream separate from saidflowing suspension of shattered coal particles in expanded steam, anoxygen-containing gas capable of reacting at an elevated temperaturewith said coal particles to form a caloric gas; maintaining said vortexat from 1800" to 2800 F. to bring about a reaction between said coalparticles and said gas generating a caloric gas; and separating residualsolid material from the resulting caloric gas at a temperature below thefusion point of said solid material.

JOI-IN I. YELLOTT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,833,964 Cross Dec. 1, 1931 2,385,508 Hammond Sept. 25, 19452,550,390 Stephanoff Apr. 24, 1951 FOREIGN PATENTS Number Country Date296,751 Great Britain Sept. 3, 1928 OTHER REFERENCES Yellott et al.:National Engineer, June 1946, pages 448-454.

1. THE METHOD OF MANUFACTURING A CALORIFIC GAS FROM GRANULAR COAL WHICHCOMPRISES PROVIDING A SOURCE OF GAS UNDER A PRESSURE OF AT LEAST FIVEPOUNDS PER SQUARE INCH; CONTINUOUSLY AND UNINTERRUPTEDLY DISCHARGINGCOMPRESSED GAS FROM SAID SOURCE WHILE CONFINING THE DISCHARGED GAS TOESTABLISH A STREAM OF COMPRESSED GAS FLOWING UNINTERRUPTEDLY ANDCONTINUOUSLY FROM SAID SOURCE TO AND PAST A DISCHARGE POINT SPACED FROMSAID SOURCE; CONCURRENTLY, CONTINUOUSLY AND UNINTERRUPTEDLY INTRODUCINGSAID GRANULAR COAL INTO SAID STREAM AHEAD OF SAID DISCHARGE POINT FORACCELERATION AND SUSPENSION OF SAID GRANULES BY SAID GAS AHEAD OF SAIDDISCHARGE POINT; AT SAID DISCHARGE POINT ESTABLISHING AND CONTINUOUSLYAND UNINTERRUPTEDLY MAINTAINING A SHARP GAS PRESSURE GRADIENT, THEPRESSURE OF SAID GRANULE-SUSPENDING GAS BEING INSTANTANEOUSLY REDUCED ASSAID GRANULE SUSPENDING GAS CONTINUOUSLY AND UNINTERRUPTEDLY FLOWS PASTSAID DISCHARGE POINT; SAID STREAM OF COMPRESSED GAS HAVING ASUBSTANTIALLY UNIFORM CROSS SECTIONAL AREA UPSTREAM OF SAID DISCHARGEPOINT AND BEING SHARPLY CONSTRICTED ONLY AT SAID DISCHARGE POINT WHEREBYTHE TOTAL PRESSURE DROP IN SAID STREAM IS CONCENTRATED AT SAID DISCHARGEPOINT; THE DROP IN GAS PRESSURE AT SAID DISCHARGE POINT BEINGCONTINUOUSLY AND UNINTERRUPTEDLY MAINTAINED AT A VALUE OF AT LEAST FIVEPOUNDS PER SQUARE INCH AND THE GAS PRESSURE IMMEDIATELY DOWNSTREAM OFSAID DISCHARGE POINT BEING REDUCED AT LEAST TO A POINT WHERE FURTHERDOWNSTREAM PRESSURE REDUCTION WILL NOT BRING ABOUT A SUBSTANTIALLYINCREASED WEIGHT RATE OF FLOW PAST SAID DISCHARGE POINT; SAID COAL BEINGINTRODUCED INTO SAID STREAM IN THE FORM OF GRANULES SMALLER THAN THECROSS SECTION OF SAID STREAM AT SAID DISCHARGE POINT; EACH OF SAIDSUSPENDED GRANULES BEING CARRIED IN SUSPENSION BY SAID STREAMINGCOMPRESSED GAS ALONG A SUBSTANTIALLY STRAIGHT PATH TO AND PAST SAIDDISCHARGE POINT AND THERE FURTHER ACCELERATED AND SUBJECTED TO SAIDINSTNTANEOUS DROP IN GAS PRESSURE WHEREBY SAID GRANULES AREDISINTEGRATED AND THERE IS FORMED A FLOWING SUSPENSION OF SHATTERED COALPARTICLES IN EXPANDE GAS; IMMEDIATELY FORMING SAID SUSPENSION INTO AVORTEX; INCORPORATING WITH SAID VORTEX, IN A STEAM SEPARATE FROM SAIDFLOWING SUSPENSION OF SHATTERED COAL PARTICLES IN EXPANDED GAS, A GASCAPABLE OF REACTING AT AN ELEVATED TEMPERATURE WITH SAID COAL PARTICLESTO FORM A CALORIFIC GAS AND MAINTAINING SAID VORTEX AT AN ELEVATEDTEMPERATURE TO BRING ABOUT GENERATION OF A CALORIFIC GAS.